Uncovering the Invisible: The Role of High-density Catheters in Recognizing Fractionated Signals in Pulmonary Vein Isolation.

The HD Grid multipolar mapping catheter has emerged as an invaluable tool for greater effectiveness of pulmonary vein isolation (PVI). In the cases described here, fractionated signals seen with the HD Grid catheter at the left atrial appendage (LAA) and left superior pulmonary vein (LSPV) junction were ablated. These signals are not likely to be visualized with conventional catheters and may cause recurrences due to incomplete PVI. The directional sensitivity limitations of bipolar electrogram recordings and the unique anatomy of the LAA-LSPV ridge further contribute to the challenge of evaluating PVI. The HD Grid catheter's ability to record bipoles parallel and perpendicular to the catheter splines and its high-density mapping capabilities provide a superior means for identifying gaps in ablation and detecting the low-voltage isthmus. Furthermore, factors such as ablation quality, catheter stability, and thickness of the LAA-LSPV ridge influence the presence of fractionated signals and the success of PVI. Incorporating preprocedural imaging modalities, such as computed tomography or magnetic resonance imaging, and real-time intracardiac echocardiography could enhance the tailored approach to address these challenges. Future developments in the HD Grid technology, including the option for contact force measurement during mapping, may offer additional insights into the nature of these signals. This case series highlights the significance of using the HD Grid catheter for a detailed interrogation of the LAA-LSPV ridge, ultimately leading to more effective PVI and improved outcomes in patients with atrial fibrillation.

Mechanisms of action behind the protective effects of proactive esophageal cooling during radiofrequency catheter ablation in the left atrium.

Proactive esophageal cooling for the purpose of reducing the likelihood of ablation-related esophageal injury resulting from radiofrequency (RF) cardiac ablation procedures is increasingly being used and has been Food and Drug Administration cleared as a protective strategy during left atrial RF ablation for the treatment of atrial fibrillation. In this review, we examine the evidence supporting the use of proactive esophageal cooling and the potential mechanisms of action that reduce the likelihood of atrioesophageal fistula (AEF) formation. Although the pathophysiology behind AEF formation after thermal injury from RF ablation is not well studied, a robust literature on fistula formation in other conditions (eg, Crohn disease, cancer, and trauma) exists and the relationship to AEF formation is investigated in this review. Likewise, we examine the abundant data in the surgical literature on burn and thermal injury progression as well as the acute and chronic mitigating effects of cooling. We discuss the relationship of these data and maladaptive healing mechanisms to the well-recognized postablation pathophysiological effects after RF ablation. Finally, we review additional important considerations such as patient selection, clinical workflow, and implementation strategies for proactive esophageal cooling.

An Uncommon Focus of a Common Phenomenon: Superior Vena Cava Triggering Atrial Fibrillation.

Ablation of atrial fibrillation most commonly involves the pulmonary veins; however, the superior vena cava (SVC) is an important potentially arrhythmogenic structure that should not be overlooked. This case report demonstrates an excellent example of triggering activity localized to the SVC and the subsequent conversion to sinus rhythm with ablation of the SVC.

Atrioesophageal Fistula Rates Before and After Adoption of Active Esophageal Cooling During Atrial Fibrillation Ablation.

BACKGROUND: Active esophageal cooling reduces the incidence of endoscopically identified severe esophageal lesions during radiofrequency (RF) catheter ablation of the left atrium for the treatment of atrial fibrillation. A formal analysis of the atrioesophageal fistula (AEF) rate with active esophageal cooling has not previously been performed. OBJECTIVES: The authors aimed to compare AEF rates before and after the adoption of active esophageal cooling. METHODS: This institutional review board (IRB)-approved study was a prospective analysis of retrospective data, designed before collecting and analyzing the real-world data. The number of AEFs occurring in equivalent time frames before and after adoption of cooling using a dedicated esophageal cooling device (ensoETM, Attune Medical) were quantified across 25 prespecified hospital systems. AEF rates were then compared using generalized estimating equations robust to cluster correlation. RESULTS: A total of 14,224 patients received active esophageal cooling during RF ablation across the 25 hospital systems, which included a total of 30 separate hospitals. In the time frames before adoption of active cooling, a total of 10,962 patients received primarily luminal esophageal temperature (LET) monitoring during their RF ablations. In the preadoption cohort, a total of 16 AEFs occurred, for an AEF rate of 0.146%, in line with other published estimates for procedures using LET monitoring. In the postadoption cohort, no AEFs were found in the prespecified sites, yielding an AEF rate of 0% (P < 0.0001). CONCLUSIONS: Adoption of active esophageal cooling during RF ablation of the left atrium for the treatment of atrial fibrillation was associated with a significant reduction in AEF rate.

An interesting case of infra-hisian block.

INTRODUCTION: The management of patients with conduction disease and supraventricular arrhythmias presents a multitude of clinical challenges.Intra-Hisian block, a condition characterized by delayed or blocked electrical conduction within the His bundle, can result in debilitating symptoms, such as syncope or presyncope. This case report aims to elucidate the diagnostic and therapeutic considerations that were taken in a patient who presented with recurrent syncopal episodes that corresponded to atrial flutter (AFL) and subsequently underwent cavotricuspid isthmus ablation. CASE PRESENTATION: A 65-year-old male with paroxysmal AFL and a pre-existing right bundle branch block and left anterior fascicular block (RBBB+LAFB) experienced recurrent syncopal episodes that were found to be correlated with AFL episodes. Following CTI ablation, an electrophysiology study (EPS) revealed a prolonged HV interval of 101ms, which indicated potential conduction abnormalities. With coronary sinus pacing, an intra-Hisian delay of 211ms was observed. During instances of atrioventricular block, intra-Hisian delay was evident on conducted beats, followed by intra-Hisian block on non-conducted beats. Ultimately, the patient's syncopal episodes prompted the placement of a dual-chamber pacemaker, which resulted in the resolution of symptoms. CONCLUSION: Intra-Hisian block is a condition that is often associated with delayed or blocked electrical conduction within the His bundle. When symptomatic, patients often present with syncope or presyncope. Etiologies of this condition include degenerative changes, myocardial infarction, autoimmune disorders, infections, medications, and more. This case emphasizes the importance of electrophysiology studies (EPS) in the diagnosis and management of patients with intra-Hisian block. Prompt intervention, such as the placement of a dual-chamber pacemaker, can alleviate symptoms and improve patient outcomes. Thus, clinical awareness and utilization of EPS can aid in accurate diagnosis and appropriate treatment selection for patients with conduction abnormalities and supraventricular arrhythmias.cuspid isthmus (CTI) ablation.

Epicardial Potential in the Left Atrium During Posterior Wall Isolation in Persistent Atrial Fibrillation.

Pulmonary vein isolation (PVI) is used for rhythm control in atrial fibrillation (AF). Posterior wall isolation (PWI) is often an adjunct to PVI. Successful PWI is limited by esophageal location, epicardial bridging signals, tissue thickness, and mapping catheter resolution. High-density grid mapping catheters can assist with PWI. Here, we report a case of a 71-year-old woman with persistent AF who underwent PVI and PWI with high-density grid mapping catheters, thus demonstrating the use of omnipolar technology in facilitating successful PWI.

Improved left atrial appendage closure procedural efficiency using radiofrequency transseptal wire system.

OBJECTIVE: The radiofrequency (RF) needle has been shown to improve transseptal puncture efficiency and safety compared to mechanical needles. This study aimed to investigate the use of VersaCross RF transseptal wire system (Baylis Medical) to improve procedural efficiency of left atrial appendage closure (LAAC) compared to the standard RF needle-based workflow. METHODS: Eighty-one LAAC procedures using WATCHMAN FLX were retrospectively analyzed comparing the standard RF needle-based workflow to a RF wire-based workflow. Study primary endpoint was time to WATCHMAN device release, and secondary endpoints were transseptal puncture time, LAAC success, fluoroscopy use, and procedural complications. RESULTS: Twenty-five cases using standard RF needle-based workflow were compared to 56 cases using the RF wire-based workflow. Baseline patient characteristics were similar between both groups. LAAC was successful in all patients with no differences in intraprocedural complication rates (p = 0.40). Transseptal puncture time was 1.3 min faster using the RF wire-based workflow compared to the standard RF needle-based workflow (6.5 ± 2.3  vs. 7.8 ± 2.3 min, p = 0.02). Overall, time to final WATCHMAN device release was 4.5 min faster with the RF wire-based workflow compared to the RF needle-based workflow (24.6 ± 5.6 vs. 29.1 ± 9.6 min, p = 0.01). Fluoroscopy time was 21% lower using the RF wire-based workflow (7.6 ± 2.8 vs. 9.6 ± 4.4 min; p = 0.05) and fluoroscopy dose was 67% lower (47.1 ± 35.3 vs. 144.9 ± 156.9 mGy, p = 0.04) and more consistent (F-test, p ˂ 0.0001). CONCLUSIONS: The RF wire-based workflow streamlines LAAC procedures, improving LAAC efficiency and safety by reducing fluoroscopy, device exchanges, and delivery sheath manipulation.

Implantable Cardioverter-defibrillator Magnetic Interference by the iPhone 12: Is It Clinically Significant?

The iPhone 12 series (Apple, Inc., Cupertino, CA, USA) contains a circular array of magnets around a central charging coil (compatible with "Magsafe" technology). The device was recently reported to have magnetic interference with implantable cardioverter-defibrillators (ICDs). We sought to test the electromagnetic interference of the iPhone 12 in inhibiting life-saving therapies of ICDs in clinical settings. After obtaining written informed consent, an iPhone 12 was placed over the device generators of 17 patients in the ICD clinic. Device interrogation was performed immediately before and after placing the iPhone over the ICD generator to evaluate for any inhibition of device therapies. To emulate a real-world scenario, the iPhone 12 was not placed directly over the skin above the device generator but instead was positioned over the patients' clothes. None of the device interrogations revealed interruption of device therapies due to the iPhone. We concluded that, despite the iPhone having shown in vitro interference of ICD functioning, its effects are not clinically relevant in vivo. Larger studies need to be performed to confirm this finding and guide safety recommendations regarding the use of iPhones containing magnets by patients with implanted ICDs.

Choice of Steerable Sheath Impacts Contact Force Stability During Pulmonary Vein Isolation.

A stable contact force (CF) is correlated with more effective radiofrequency (RF) ablation (RFA) lesions and long-term procedural outcomes. Efforts to improve catheter stability include jet ventilation, pacing, steerable sheaths, and CF-sensing ablation catheters. This study compares CF stability and effective RF lesions between two commercially available steerable sheaths. Thirty patients underwent first-time RFA at a single center using the Agilis™ NxT (Abbott, Chicago, IL, USA) or SureFlex™ (Baylis Medical, Montreal, Canada) steerable sheath. High-power short-duration RFA was utilized, targeting a 10-Ω drop. Sheath performance was assessed for the entire procedure and around each pulmonary vein (PV) in terms of mean CF, CF variability, RF time per lesion, and inefficient contact lesions (defined as lesions with a CF of less than 5 g for at least 10% of the RF delivery time). The operator-targeted mean CF was achieved using both sheaths; however, the overall CF variability was 12.8% lower when using the SureFlex™ sheath (p = 0.08). The CF variability was generally 16% greater in the right PVs than the left PVs (p = 0.001) but trended lower with the SureFlex™ sheath. There were 8% more inefficient contact lesions created when using the Agilis™ sheath as compared to the SureFlex™ sheath (p = 0.035), especially in the right inferior PV (p = 0.009). The RF time per lesion was, on average, 12% (1.4 seconds) shorter when using the SureFlex™ sheath than the Agilis™ sheath (p < 0.05). The choice of steerable sheath may affect both catheter stability and lesion quality, especially in the right PVs.

Long-term use of the wearable cardioverter defibrillator in patients with explanted ICD.

OBJECTIVES: To evaluate the effectiveness of wearable cardioverter defibrillator (WCD) use in protecting patients from sudden cardiac arrest (SCA) while they were treated in nonhospital settings until re-implantation of an Implantable cardioverter-defibrillator (ICD) was feasible. We sought to determine whether the WCD could be successfully utilized long term (≥1 year) after ICD extraction in patients at continued risk of SCD in which ICD re-implantation was not practical. BACKGROUND: ICDs have proven to improve mortality in patients for both secondary and primary prevention of SCA. Increased ICD implantation in older patients with comorbid conditions has resulted in higher rates of cardiac device infections. Currently, a wearable cardioverter defibrillator (WCD) is an alternative management for SCA prevention in specific cases. METHODS: This a retrospective analysis based on consecutive WCD patients who underwent ICD explant due to device-related infections or mechanical reasons between April 2007 and July 2014. A total of 102 patients were identified from the national database maintained by ZOLL (Pittsburgh, PA, USA). We analyzed the reason for WCD use, demographic information, device data, compliance and duration of WCD use, detected arrhythmias and therapies, and reason for discontinuing WCD use. RESULTS: In these long term WCD users, average length of WCD use was 638 ±â€¯361 days. Nine patients (8.8%) had a sustained ventricular arrhythmia that was successfully resuscitated by the WCD. Six patients (5.8%) experienced inappropriate shocks. Two patients (1.9%) died of asystole events while wearing the WCD and an additional 10 patients died while not monitored by the WCD. Thirty-nine patients (38.2%) ended WCD use when a new ICD was implanted and 15 patients (14.7%) were still wearing the WCD at the time of analysis. CONCLUSIONS: We found that extending use of the WCD to ≥1 year is a safe and effective alternative treatment for patients with explanted ICDs who are not pacemaker dependent.

Successful fluoroless radiofrequency catheter ablation of supraventricular tachycardia during pregnancy.

Even in the absence of underlying heart disease, pregnancy is known to increase susceptibility supraventricular tachycardia (SVT). This brings a management challenge, mainly due to concerns about pharmacotherapy and radiation to the fetus. This case highlights the capability of using fluoroless mapping technologies to treat refractory arrhythmia cases safely and successful.

Concomitant Wolff-Parkinson-White and Atrioventricular Nodal Reentrant Tachycardia: Which Pathway to Ablate?

BACKGROUND: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common form of supraventricular tachycardia. In contrast, Wolff-Parkinson-White (WPW) pattern consists of an accessory pathway, which may result in the development of ventricular arrhythmias. Frequent tachycardia caused by AVNRT and accessory pathways may play a role in left ventricular systolic dysfunction. CASE REPORT: A 54-year-old man presented with palpitations and acute decompensated congestive heart failure. His baseline EKG showed Wolff-Parkinson-White (WPW) pattern. While hospitalized, he had an episode of atrioventricular nodal reentrant tachycardia (AVNRT). He underwent radiofrequency catheter ablation for AVNRT, and his accessory pathway was also ablated even though its conduction was found to be weak. He was clinically doing well on follow-up visit, with resolution of his heart failure symptoms and normalization of left ventricular function on echocardiography. CONCLUSIONS: This case raises the question whether the accessory pathway plays a role in the development of systolic dysfunction, and if there is any role for ablation in patients with asymptomatic WPW pattern.

Outcome of percutaneous continuous drainage of psoas abscess: A clinically guided technique.

BACKGROUND: Percutaneous aspiration of abscesses under ultrasonography (USG) and computer tomography (CT) scan has been well described. With recurrence rate reported as high as 66%. The open drainage and percutaneous continuous drainage (PCD) has reduced the recurrence rate. The disadvantage of PCD under CT is radiation hazard and problems of asepsis. Hence a technique of clinically guided percutaneous continuous drainage of the psoas abscess without real-time imaging overcomes these problems. We describe clinically guided PCD of psoas abscess and its outcome. MATERIALS AND METHODS: Twenty-nine patients with dorsolumbar spondylodiscitis without gross neural deficit with psoas abscess of size >5 cm were selected for PCD. It was done as a day care procedure under local anesthesia. Sequentially, aspiration followed by guide pin-guided trocar and catheter insertion was done without image guidance. Culture sensitivity was done and chemotherapy initiated and catheter kept till the drainage was <10 ml for 48 hours. Outcome assessment was done with relief of pain, successful abscess drainage and ODI (Oswestry Disability Index) score at 2 years. RESULTS: PCD was successful in all cases. Back and radicular pain improved in all cases. Average procedure time was 24.30 minutes, drain output was 234.40 ml, and the drainage duration was 7.90 days. One patient required surgical stabilisation due to progression of the spondylodiscitis resulting in instability inspite of successful drainage of abscess. Problems with the procedure were noticed in six patients. Multiple attempts (n = 2), persistent discharge (n = 1) for 2 weeks, blocked catheter (n = 2) and catheter pull out (n = 1) occurred with no effect on the outcome. The average ODI score improved from 62.47 to 5.51 at 2 years. CONCLUSIONS: Clinically guided PCD is an efficient, safe and easy procedure in drainage of psoas abscess.

Ranolazine safely decreases ventricular and atrial fibrillation in Timothy syndrome (LQT8).

Long QT eight (LQT8), otherwise known as Timothy syndrome (TS), is a genetic disorder causing hyper-activation of the L-type calcium channel Cav 1.2. This calcium load and the resultant increase in the QT interval provide the substrate for ventricular arrhythmias. We previously presented a case in a patient with TS who had a profound decrease in his burden of ventricular arrhythmias after institution of an L-type calcium channel blocker. Although this patient's arrhythmia burden had decreased, he displayed an increasing burden of atrial fibrillation and still had bouts of ventricular fibrillation requiring defibrillator therapy. Basic research has recently shown that ranolazine, a multipotent ion-channel blocker, may be of benefit in patients with LQT8 syndrome. This case report details the decrease of atrial fibrillation and ventricular fibrillation events in our LQT8 patient with the addition of ranolazine.